An air cleaner is a device installed on an internal combustion engine to provide clean air for combustion within the engine cylinder. Heavy duty air cleaners are typically used on engines that power devices used for industrial purposes, for example construction equipment or agricultural equipment.
FIG. 1 (Prior Art) provides a perspective, partially-exploded view of a typical conventional heavy duty air cleaner assembly 0. As shown in FIG. 1, the air cleaner assembly 0 includes an air cleaner 3 having a tubular shaped housing 4 and a filter element 8 that uses pleated paper to filter dust and other debris out of the combustion air flow. The filter element 8 is placed inside the tubular shaped housing 4, and is designed to provide a large filter paper surface area to increase the time the engine can be operated before cleaning or replacing the filter element. A removable end cap 5 can be affixed to and removed from the housing 4 to provide access to the filter element 8, allowing replacement or servicing of the filter element. The end cap 5 in the present view is shown to be attached to the housing 4 even though the filter element 8 is shown disassembled from (and outside of) the housing.
In addition to the housing 4, end cap 5, and filter element 8, FIG. 1 shows the air cleaner 3 to include a number of other components. In particular, the air cleaner 3 includes a mushroom-shaped rain cap 1 that is configured to be positioned onto (and over) an upwardly-extending input port 28 of the housing 4. Also, the air cleaner includes cover retaining clips 6 by which the end cap 5 is fastened to the housing 4, a dirt ejection valve 7, and a secondary or redundant filter element 9 (sometimes referred to as a “safety” filter element) that fits concentrically within an inner cylindrical space within the filter element 8 when the filter elements are installed within the housing. It should be noted that FIG. 1 shows the filter elements 8, 9 to be in positions that are approximately 180 degrees different from those the filter elements would occupy when implemented within the housing 4 and end cap 5 as shown, in order to show open ends of those filter elements that only exist at one of the two axial ends of each respective filter element.
The air cleaner assembly 0 further includes, in addition to the components of the air cleaner 3, an air duct 11, an adapter (air duct to carburetor) 13, gaskets 14 and 17, hose clamps 10, air cleaner brackets 18 and 24, and an air cleaner body clamp 20. Typically, the filtered air output at an output port 29 of the air cleaner 3 is ducted to a carburetor or throttle body on a spark ignited engine, or to an intake manifold on compression ignition engines. In the present embodiment, the air cleaner assembly 0 is shown to include the intake manifold 15. Also, the air cleaner assembly 0 includes various fastening components 2, 12, 16, 19, 21, 22, 23, and 25, which can include, for example, bolts, washers, screws, etc. The air cleaner 3 is mounted upon the engine by way of certain of these fastening components, along with the air cleaner brackets 18, 24 and the body clamp 20, which is coupled to the air cleaner brackets and surrounds the tubular housing 4. Also, the fastening component 2 is used to clamp the rain cap 1 to the input port 28.
To further extend the service life of the filter element 8, the tubular housing 4 of the air cleaner 3 is designed to spin the incoming air within the air cleaner, particularly within an annular space existing between the outer wall of the housing (and end cap 5) and the filter element 8 positioned within the housing. Dirt particles suspended in the incoming air centrifuge out against the outer walls of the tubular housing 4, eventually reaching the dirt ejection valve 7, which allows for the dirt to exit the air cleaner 3. Thus, the amount of dirt and dust that reaches the filter element 8 is significantly reduced. Further, the rain cap 1 is installed onto the input port 28 of the housing 4 to prevent ingestion of moisture and to prevent other large debris from entering the housing.
While relatively heavy dirt particles tend to exit the air cleaner 3 by way of the dirt ejection valve 7, the otherwise unfiltered air continues through the air cleaner 3 by passing radially inward through the tubular pleated paper of the filter element 8, and then proceeds further radially inward through the secondary filter element 9 as well, until the air reaches a central axial tubular passage within the secondary filter element. The filtered air then passes through and out of the axial tubular passage by way of the output port 29 of the tubular housing 4. The filtered air exiting the output port 29 of the tubular housing 4 then is ducted to the engine.
As mentioned, FIG. 1 shows the air cleaner 3 employed as a heavy duty air cleaner in connection with the intake manifold 15. When the air cleaner assembly 0 is assembled and installed in relation to an engine (not shown), the air duct 11 is coupled between the output port 29 of the air cleaner 3 and the adapter 13 by way of the hose clamps 10 (and related fastening components), where the adapter 13 in turn is coupled to the intake manifold 15 with one of the gaskets 14 positioned therebetween. The air duct 11, which can be a rubber hose, thus conducts the filtered air into the engine intake manifold 15 by way of the adapter 13. The hose clamps 10 are used to provide air tight seals between the air duct 11 and each of the output port 29 of the air cleaner housing 4 and the adapter 13 (or, in cases where the adapter is not used, to the intake manifold itself).
Although conventional air cleaners such as that of FIG. 1 successfully filter air, it would be desirable if certain aspects of such air cleaners could be improved. For example, with respect to the rain cap 1 as can be used on such air cleaners, the rain cap is not ideal insofar as it constitutes an additional, large component that protrudes off of the housing. Not only is the protruding rain cap vulnerable to being knocked off of the air cleaner assembly, but also it increases the overall size of the air cleaner assembly 0 in a manner that makes it more cumbersome to install and use. This can particularly limit the applicability of the air cleaner 3/air cleaner assembly 0 in some circumstances where a smaller device is required.
Further for example, while conventional air cleaners such as the air cleaner 3 are designed to achieve a swirling, helical motion of the unfiltered air as it enters into the air cleaner housing, such air cleaners typically only have a chamber that, due to the shape of interior wall, positively influences the air to take this path over the course of about 90 degrees. Because of the limited degree to which the air is influenced to take on the swirling motion, the swirling motion imparted to the unfiltered air is often not as strong as might be desirable in order to achieve maximal centrifugal force action upon dirt particles and other large debris such that such particles and debris are directed away from the filter element within the air cleaner.
Additionally, the manner in which the air cleaner 3 is coupled to the intake manifold 15 and/or other portions of the engine on which the air cleaner is mounted requires a large number of components (e.g., the air duct 11, the hose clamps 10, the adapter 13, the body clamp 20, numerous assorted fastening devices, etc.). Consequently, assembly of the air cleaner 3 onto an engine can be a relatively complicated operation. For example, it can be relatively difficult or time-consuming to assemble the air duct 11 in conjunction with the housing 4 and the adapter/intake manifold 13, 15 in a sealed, airtight manner. Further, because of the large number of parts, the costs associated with not only the assembly of the air cleaner 3 onto an engine but also the manufacturing of the components of the air cleaner assembly 0 are higher than what they might desirably be.
Therefore, it would be advantageous if an improved design for an air cleaner assembly could be achieved. In particular, in at least some embodiments, it would be advantageous if a cumbersome mushroom-shaped rain cap atop a protruding, upwardly-extending air cleaner input port was not necessary, and/or if the air cleaner assembly was a package of smaller size or more practical shape so as to allow the air cleaner assembly to be implemented in smaller spaces or in certain applications requiring such smaller packages or packages of a less cumbersome size or shape. Also, in at least some embodiments, it would be advantageous if the swirling action within the air cleaner could be enhanced. Further, in at least some embodiments, it would be advantageous if the number and complexity of parts used in assembling the air cleaner to an engine/intake manifold could be reduced.